Simultaneously achieving fast sulfur redox kinetics and high-loading in lithium–sulfur batteries

Abstract

For lithium-sulfur batteries (LSBs), searching for highly efficient host that allows for high sulfur loading and excellent lithium polysulfides (LiPSs) trapping capability is extremely important. Herein, a systematical study with regard to both experimental and theoretical of N/S heteroatoms co-doped polar surface (denoted as NSHC) is conducted to demonstrate the significance of rational structure design as well as rapid sulfur related redox kinetics for high loading cathode. With prominent merits in both heteroatoms doping and hierarchical structure, the as-fabricated NSHC/S cathode guarantees extraordinary sulfur storage, which enables fast sulfur electrochemistry under the conditions of high sulfur loading (6.72 mg cm−2), high sulfur content (80 wt%) and lean electrolyte usage (electrolyte/sulfur ratio: 7.5 μL mg−1). Of particular emphasis is the compact and high utilization of the host structure that ensures the assembled LSB with long and stable durability (606 mAh·g−1 after 100 cycles at 0.1 C and sulfur loading of 6.72 mg cm−2) and superior rate performance (689 mAh·g−1 at 5.0 C and sulfur loading of 2 mg cm−2).